Ureteral access sheath

ABSTRACT

A ureteral access sheath adapted for insertion into a urethra includes an elongate tube extending between a proximal end and a distal end. A handle assembly is disposed at the proximal end and includes enlarged portions which inhibit migration of the sheath into the urethra. The enlarged portions are shaped like the bell of a horn with a concave, distally-facing outer surface and a convex, proximally-facing inner surface. The inner surface functions as a funnel while the outer surface is sized and configured to receive adjacent fingers of a user&#39;s hand held in its natural position. In an associated method, this shape of the handle assembly facilitates maintaining the sheath in a stationary position during insertion and removal of instrumentation. The handle assembly can be movable on the tube to facilitate variation of the sheath link in situ.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates generally to guideways for endoluminalaccess and more specifically to surgical access devices adapted tointroduce surgical instrumentation into body conduits.

[0003] 2. Discussion of the Prior Art

[0004] Surgical access devices of the prior art typically include asheath having an outside diameter and an inside diameter. An obturatoror dilator is inserted into the sheath to facilitate introduction of thesheath into the body conduit. Once the sheath is positioned, theobturator is removed leaving a working channel for surgicalinstrumentation.

[0005] Particularly in the field of urology, the sheath has beenprovided in the form of an elongate tube having an axis extendingbetween a proximal end and a distal end. The diameter of the tube isgenerally constant, except for a reduced diameter segment at the distalend. Although the obturator has had an enlarged structure at itsproximal end, there has been no such enlargement for the sheath. Thishas presented a problem as the sheath has tended to migrate distally anddisappear beneath the urethral meatus. Representative of this art is theFLEXIBLE URETEROSCOPE SHEATH manufactured and sold by Cook UrologicalIncorporated.

[0006] Access devices particularly adapted for other body conduits havehad enlargements at the proximal end, but these have not beenspecifically configured to prevent migration or facilitate theintroduction of instrumentation. Representative of this art are the“banana peel” sheaths which split axially for removal after catheterplacement.

[0007] During the introduction and removal of dilators, obturators, andinstrumentation into and out of a sheath, it is always desirable tofacilitate maintenance of the sheath in a relatively stationaryorientation. In the past, there has been no handle structure which wassized and shaped to accommodate engagement by a user's hand disposed inits natural position with the palm facing the user. Nor has there beenany progressive funnel structure which would facilitate the introductionof instrumentation into the working channel of the sheath.

SUMMARY OF THE INVENTION

[0008] These deficiencies of the prior art have been eliminated with thepresent access device which includes a sheath having at its proximal enda handle specifically adapted to inhibit migration and facilitate usewith instrumentation. The handle is formed as a radial enlargementhaving a distally-facing surface and a proximally-facing surface. Thedistally-facing surface has a generally concave configuration whichprovides a gradual enlargement inhibiting migration of the sheath intothe ureter. The concave configuration is sized to receive adjacentfingers of a user's hand disposed in its natural position, in order tofacilitate the stationary orientation of the sheath. The concave,distally-facing surface is continuous around the axis of the sheath sothat the advantage of this concave configuration can be appreciatedregardless of the radial orientation of the sheath.

[0009] The proximal-facing surface has a generally convex configurationproviding for an increased funneling of an instrument as it is insertedinto the working channel of the sheath. Both the distally-facing surfaceand the proximally-facing surface extend radially inwardly withprogressively equal distal positions along the sheath. This provides thehandle with the general shape of the bell of a horn. This configurationis not only ergonomically comfortable, but highly practical inaddressing the problems of migration, as well as instrument insertionand removal.

[0010] The handle can be provided with characteristics permitting thehandle to be moved to a preferred position along the tube of the sheath,and then to be fixed to the tube at that preferred location. This makesit possible to provide the sheath with any desired length, even after ithas been inserted into the body conduit. A metal structure such as aspring, can be molded into the tube of the sheath to facilitate kinkresistance.

[0011] The inner dilator can be provided with a Luerlock end, permittingattachment of a sidearm adaptor (not shown). This allows forinstallation of contrast during sheath placement without the need toremove the guidewire.

[0012] These and other features and advantages of the invention willbecome more apparent with a description of preferred embodiments andreference to the associated drawings.

DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 is a perspective view illustrating a sheath of the presentinvention with an obturator or dilator adapted for use with the sheath;

[0014]FIG. 2 is a perspective view illustrating the obturatoroperatively disposed within the sheath;

[0015]FIG. 3 is an axial cross-section view taken along lines 3-3 ofFIG. 2 and illustrating the obturator operatively disposed within a tubeand “handle” of the sheath;

[0016]FIG. 4 is an enlarged radial cross-section view of the handleassembly illustrated in FIG. 3;

[0017]FIG. 5 is a side-elevation view of the sheath and obturatoroperatively disposed in the urethra and illustrating a preferredconfiguration for the handle assembly of the sheath;

[0018]FIG. 6 is a side-elevation view similar to FIG. 5 of a furtherembodiment of the handle assembly of the present invention;

[0019]FIG. 7 is a side-elevation view partially in phantom and explodedto illustrate components of another preferred embodiment of the handleassembly providing for sheath length adjustment;

[0020]FIG. 8 is a side-elevation view illustrating the components ofFIG. 7 in an assembled configuration;

[0021]FIG. 9 is a radial cross-section view taken along lines 9-9 ofFIG. 8;

[0022]FIG. 10 is a perspective, disassembled view of a furtherembodiment of a handle assembly permitting length adjustment;

[0023]FIG. 11 is a perspective, assembled view of the componentsillustrated in FIG. 10; and

[0024]FIG. 12 is a side-elevation view partially in fragment andillustrating a spring embodiment of the tube associated with the sheathof the present invention.

DESCRIPTION OF PREFERRED EMBODIMENTS AND BEST MODE OF THE INVENTION

[0025] A ureteral access sheath is illustrated in FIG. 1 and designatedgenerally by the reference numeral 10. In FIG. 1, the sheath 10 isillustrated in combination with a separate, but associated, dilator orobturator 12. The sheath 10 has the general configuration of an elongatetube 14 having an axis 16 which extends between a proximal end 18 and adistal end 21. A handle 23 is disposed at the proximal end 18 of thetube 14 and provides access into a working channel 25 of the tube 14.

[0026] The obturator 12 will typically have the configuration of anelongate rod 30 extending between a proximal end 32 and a distal end 34.A knob 36 is disposed at the proximal end 32 and a tapered tip 38 isformed at the distal end 34. The obturator 12 is adapted to be insertedinto the working channel 25 of the sheath 10 with the knob 36 extendingproximally of the sheath 10, and the distal end 34 extending distally ofthe sheath 10. This operative position of the obturator 12 within thesheath 10 is illustrated in the assembled view of FIG. 2. An axialcross-section view of the assembled combination is illustrated in FIG. 3where the rod 30 of the obturator 12 is more clearly shown within theworking channel 25 of the sheath 10.

[0027] If desired, the releasable lock (not shown) can be provided toremovably attach the obturator 12 to the sheath 10. When locked inplace, the obturator 12 and sheath 10 can then be passed as a singleunit over the guidewire. This arrangement precludes inadvertentadvancement of the sheath 10 in front of the obturator 12, which couldgreatly impede proper passage of the sheath and potentially the ureter.

[0028] The handle 23 associated with the sheath 10 is of particularinterest to the invention and is illustrated in the enlarged, axialcross-section view of FIG. 4. From this view it can be seen that thehandle 23 has the general configuration of the bell of a horn. Thehandle 23 has a distally-facing surface 41 on the outside of the handle23, and a proximally-facing surface 43 on the inside of the handle 23.Both of these surfaces 41 and 43 in the preferred embodiment arecontinuous and have a generally conical configuration. In theillustrated embodiment, the distally-facing surface 41 is generallyconcave, while the proximally-facing surface 43 is generally convex.

[0029] The handle 23 can be provided with two small holes 45, 46 forpassage of sutures 47 and 48, respectively. Once the sheath is in place,the sutures 47, 48 can be clamped with hemostats (not shown) to thesurgical drapes, thereby preventing distal migration of the sheath andloss of ureteral access. Once the obturator/sheath combination has beenadvanced to the desired position in the ureter, the obturator 12 can beunlocked from the sheath 10 and removed. In the manner discussed ingreater detail below, these features offer particular advantages to thepresent invention.

[0030] One of the purposes of the proximally-facing surface 43 is tofunnel the obturator 12 and other surgical instrumentation into theworking channel 25 of the sheath 10. With the generally conicalconfiguration, this proximally-facing surface functions as a funnel witha radius which decreases with progressive distal positions along theaxis 16. Thus, as the instrumentation is moved distally, theproximally-facing surface 43 guides the instrument along a decreasinglydecreasing radius into the working channel 25 of the sheath 10.Providing the surface 43 with a generally convex configuration furtherfacilitates this funneling feature of the invention. When the surface 43is convex, its radius decreases at a decreasing rate with progressivelyequal distal positions along the axis 16.

[0031] The distally-facing surface 41 is intended to facilitateengagement of the sheath 10 by a user's hand held in its most naturalstate. In FIG. 5, adjacent fingers 50 and 52 of the user's hands areillustrated schematically by the circles 50 and 52. In the naturalstate, the palm of the user's hands would be facing the user in theproximal direction, to the left in FIG. 5. The sheath 10 is adapted tobe operatively positioned between the fingers 50 and 52 with the handle23 positioned so that the distally-facing surface 41 is in juxtapositionto the fingers 50 and 52. This fit is facilitated by forming the surface41 with a size and configuration generally similar to the fingers 50 and52, as illustrated in FIG. 5. Thus, with the distally-facing surface 41having a generally conical configuration, it has a radius whichdecreases with progressive distal positions along the axis 16. In anembodiment wherein the surface 41 is also concave, the radius of thesurface 41 decreases at a decreasing rate with progressively equaldistal positions along the axis 16.

[0032] In operation, as the surgical instrument, such as the obturator12, is inserted into the handle 23, it produces a force F₁ (illustratedby arrow 54) in the distal direction. This force is opposed by thefingers 50 and 52, which engage the distally-facing surface 43 and applyopposing forces F₂ and F₃ (represented by arrows 56 and 58). In thismanner, the fingers 50 and 52 can maintain the sheath 10 generallystationary even when the obturator 12 is being inserted. It will also benoted that with the user's hand in the natural position, it tends toform a barrier which prevents any instrumentation from extendingexteriorly beyond the handle 23 into contact with ureteral tissue 60.

[0033] Although the embodiment of FIG. 5 is particularly adapted tofacilitate insertion of a surgical instrument, such as the obturator 12,it will be appreciated that removal of the instrument also createswithdrawal forces on the sheath 10. A further embodiment of the handlewhich can easily accommodate not only insertion forces but alsowithdrawal forces, is illustrated in FIG. 6. In this embodiment, ahandle 61 is similar to the handle 23, except that the outer,distally-facing surface 43 is curved distally outwardly to form aproximally-facing outer surface 63. In this case, the two surfaces 41and 63 form a continuous surface which defines an annular recess sizedand configured to receive the fingers 50 and 52.

[0034] In this embodiment, insertion of the instrument, such as theobturator 12, is resisted by the forces F₂ and F₃ applied by the fingers50 and 52, respectively, to the distally-facing surface 43, aspreviously discussed with reference to FIG. 5. In a similar manner, whenthe instrument such as the obturator 12 is withdrawn, it produces aforce F₄ (illustrated by arrow 65) which must be resisted in order tomaintain the sheath 10 stationary. This resistance is provided in theembodiment of FIG. 6 by the pressure of the fingers 50, 52 against theproximally-facing outer surface 63. Thus, fingers 50, 52 provideopposing forces F₁ and F₆ designated by arrows 67, 70, respectively.

[0035] FIGS. 7-9 illustrated a further embodiment involving a handle,such as the handles 23 or 61, which is movable relative to the tube 14of the sheath 10. This embodiment is particularly desirable as itpermits the tube 14 to be cut in situ, at the operative site, to apreferred length. With a sheath of this type, only a single accessdevice need be present at the operative site. Multiple sheaths havingdifferent lengths are not required to be present in order to have asheath of the desired length. As illustrated in FIG. 7, this embodimentof the sheath 10 includes the tube 14 which is slidingly engageable by ahandle assembly 72 that includes a sleeve 74 and a funnel 76. The sleeve74 is formed as a cylinder 77 having an interior bore 78 and externalthreads 81. An elastomeric element 83 is disposed within the bore 78 andis provided with an axial lumen 84 appropriately sized to receive thetube 14.

[0036] The funnel 76 is formed similar to the handle 23, but includestwo concentric cylinders 85 and 87 which extend distally. The outercylinder 85 is provided with interior threads 90, which are sized toreceive the external threads 81 of the sleeve 74. The inner cylinder 87of the funnel 76 is provided with an outer diameter less than the innerdiameter of the bore 78. This inner cylinder 87 extends to a distalsurface 92.

[0037] In operation, the funnel 76 is moved axially over the sleeve 74and the internal threads 90 are screwed onto the external threads 81.Further rotation of the funnel 76 relative to the sleeve 74, causes thedistal surface 92 of the inner cylinder 87 to axially compress theelastomeric element 83. This compression causes the element 83 to expandinwardly decreasing the diameter of its lumen 84 and thereby increasingthe frictional engagement of the handle assembly 72 relative to the tube14.

[0038] In order to provide the sheath 10 with a desired length, the tube14 can be cut to a predetermined length, either before or after mountingthe handle assembly 72 on the tube 14. Axial movement of the handleassembly 72 to a desired proximal location on the tube 14 provides thesheath 10 with the desired length. Operation of the handle 72 in themanner previously discussed will fix the assembly 72 on the tube 14 atthis desired location.

[0039] In another embodiment illustrated in FIG. 10, a movable handleassembly 96 includes a funnel 98 similar to the handle 23. It alsoincludes a cylinder 99 which extends distally within portions 101 whichhave a reduced diameter. A separate finger clamp 102 includes a cylinder104 which has a diameter which is dependent upon operation of fingertabs 103 and 105. When these tabs 103 and 105 are compressed, thecylinder 104 has a relatively large diameter. When the tabs 103 and 105are not compressed, the cylinder 104 is biased toward a reduceddiameter. This finger clamp 102 is intended to be operatively disposedover the thin portions 101 of the cylinder 99, as illustrated in FIG.11. In this operative position, the entire handle assembly 96 can bemoved along the tube 14 by compressing the finger tabs 103 and 105 ofthe clamp 102. The tube 14 can then be cut, for example, with scissors106, to any desired length. Compressing the finger tabs 103 and 105 willpermit the handle assembly 96 to be moved to a distal position, asillustrated in FIG. 11, where the tabs 103 and 105 can be released tocompress the thin portions 101 and maintain the handle assembly 96 in afixed relationship with the tube 14.

[0040] A further embodiment of the invention is illustrated in theside-view of FIG. 11. In this embodiment, the tube 14 is formed with aninner plastic body 110, surrounded by a metal spring coil 112, which isfurther covered by an outer body 114. This particular embodiment of thetube 14 provides a high degree of kink resistance and can be used withany of the handle assemblies previously discussed. With this embodimentof the tube 14, the inner body 110 provides a smooth surface within thesheath 10, which facilitates passage of instrumentation. The spring coil112 adds kink resistance to the tube 14, while the outer body 114provides a suitable covering for the coils of the spring 112.

[0041] From the foregoing description of preferred embodiments, it willbe apparent that many variations on the concept of this invention willbe contemplated by those skilled in the art. For example, many differentconfigurations of the tube 14 can be used with the various handleassemblies disclosed. Furthermore, the handle assemblies can be embodiedin many different forms to provide at least one curved outer surfacewhich is sized and configured to receive the fingers of a user's hand ina normal position. The fact that this desired outer shape can becombined with a funnel configuration at the proximal end of the sheath,will add further advantages to these various embodiments.

[0042] Although exemplary embodiments of the invention have been shownand described, many other changes, modifications, and substitutions willnow be apparent to those of ordinary skill in the art, withoutnecessarily departing from the spirit and scope of this invention as setforth in the following claims.

1. A ureteral access sheath adapted for insertion into a urethra havinga first diameter, comprising: an elongate tube having a second diameterand a lumen extending between a proximal end and distal end; a handledisposed at the proximal end of the tube; portions of the handleextending radially outwardly of the tube to provide the handle with athird diameter greater than the first diameter of the body conduit;whereby, the handle portions inhibit distal migration of the proximalend of the tube into the urethra.
 2. The access sheath recited in claim1 wherein the handle portions are defined by a first surface facinggenerally distally and a second surface facing generally proximally. 3.The access sheath recited in claim 2 wherein the second surface forms afunnel leading into the lumen of the tube.
 4. The access sheath recitedin claim 3 wherein the sheath is adapted for use by a person having apair of adjacent fingers and wherein: the first surface is continuousand is both sized and configured to receive the adjacent fingers of theuser.
 5. The access sheath recited in claim 3 wherein the second surfaceis convex.
 6. The access sheath recited in claim 4 wherein the firstsurface is concave.
 7. The access sheath recited in claim 5 wherein thesecond surface extends decreasingly radially inwardly with progressiveequal distal positions along the tube.
 8. The access sheath recited inclaim 6 wherein the first surface extends decreasingly radially inwardlywith progress equal distal positions along the tube.
 9. The accesssheath recited in claim 1 wherein the elongate tube includes a helicalspring.
 10. A method for inserting a medical instrument into a urethra,comprising the steps of: providing a urethral access device having anelongate tube with a lumen extending along an axis between a proximalend and a distal end, and a handle at the proximal end of the tube;configuring the handle with a distally-facing surface andproximally-facing surface, the distally-facing surface being sized andconfigured to receive two adjacent fingers of a user's hand; insertingthe distal end of the tube into the urethra to an operating position inorder to provide access for the medical device; moving the medicaldevice distally into the proximal end of the lumen of the tube andthrough the lumen of the tube into the urethra; during the moving stepcreating a distal force on the urethral access sheath; and applying aproximal force on the distally-facing surface of the handle to opposethe distal force and maintain the access sheath in the operativeposition.
 11. The method recited in claim 10 wherein the configuringstep includes the step of forming the distally-facing surface with aconcave configuration.
 12. The method recited in claim 11 wherein theconfiguring step further comprises the step of: forming theproximally-facing surface with a convex configuration.
 13. The methodrecited in claim 10 further comprising the step of: moving the handledistally axially along the tube beyond a predetermined position;removing a portion of the tube extending generally proximally of thepredetermined position; moving this handle axially proximally to thepredetermined position along the tube; and
 14. The method recited inclaim 14 further comprising the step of: facilitating a generally fixedrelationship between the handle and the tube at the predeterminedposition.
 15. A handle adapted for use with a surgical access devicehaving the configuration of an elongate tube with a working channel,comprising: a distal section of the handle sized and configured to moveon the tube of the access device to a predetermined position along thetube; a proximal section of the handle having a flared configuration anda surface facing generally proximally, the surface extending radiallyinwardly with progressive distal positions along the handle.
 16. Thehandle recited in claim 15 wherein the distal section includes:engagement apparatus movable radially inwardly to facilitate a generallyfixed relationship between the tube and the handle when the handle isoperatively disposed at the predetermined position along the tube. 17.The handle recited in claim 16 wherein the tube of the access device isformed with a plurality of annular bumps disposed along the tube, andthe engagement apparatus of the handle includes: a detent adapted toengage a predetermined one of the bumps at the predetermined location.18. The handle recited in claim 16 wherein the engagement apparatus hasa first state facilitating movement of the handle along the tube and asecond state facilitating the generally fixed relationship between thehandle and the tube at the predetermined position along the tube. 19.The handle recited in claim 18 wherein the engagement apparatus isbiased to the second state.
 20. The handle recited in claim 18 whereinthe engagement apparatus comprises: an elastomeric washer disposedaround the tube; and a nut operable to compress the washer against thetube to facilitate the fixed relationship between the handle and thetube at the predetermined position.
 21. A method for providing asurgical access with a desirable length, comprising steps of: providingan elongate tube having a working channel and a handle assembly havingan engagement apparatus adapted to fit over the tube, the handle havinga movable relationship with the tube when the engagement apparatus is ina first state and a fixed relationship with the tube when the engagementapparatus is in a second state; placing the engagement apparatus in thefirst state; removing a portion of the elongate tube to shorten thelength of the tube generally to the desired length; moving the handle toa predetermined location along the tube; and placing the engagementapparatus in the second state to fix the handle to the tube at thepredetermined location and provide the access device with the desiredlength.
 22. The method recited in claim 21 wherein the second providingstep includes the step of providing the engagement apparatus with anelastomeric washer sized and configured to fit around the tube; and thesecond placing step includes the step of compressing the washer aroundthe tube.